Quantum dots are nanometer-sized or micrometer-sized semiconductor structures in which one to a few thousand charge carriers (e.g., electrons) are confined. Such structures are useful in a variety of optical applications because they exhibit narrow spectral emission properties and rapid excited electron decay rates. In device structures, quantum dots possess superior optical properties, in part because they can provide three-dimensional electron confinement.
Quantum dots can be employed in a variety of electronic applications, e.g., to form lasers, LED devices, and photodetectors. Further, the small size of these structures make them particularly useful in assays, diagnostic systems and therapeutic compositions.
Quantum dots can be utilized in numerous biological applications, such as genomics and proteomics, as fluorescent biomarkers. For example, quantum dots can be linked to, or conjugated with, bioactive agents having an affinity to specific cells, e.g., cells having a particular malignancy. The coated quantum dots can be applied to tissue samples suspected of having such cells to attach to the selected cells, if present. Any quantum dots not attached to a cell can be washed away. Subsequently, an excitation source, e.g., a laser, illuminate the sample to cause the remaining quantum dots, which are attached to the cells, to emit a detectable emission.
Similar to the optoelectronic applications, it is desirable in biological applications that the quantum dots exhibit size uniformity and narrow spectral emissions. However, despite many recent advances in fabricating quantum dots, large scale production of quantum dots having size uniformity, in a controllable manner, has proven difficult. Currently available quantum dots typically suffer from size non-uniformities that can result in spectral broadening and weakening of photon emission.
Hence, it is desirable to provide methods for generating a plurality of quantum dots having enhanced size uniformity. It is also desirable to provide such methods that allow generating quantum dots in a controllable and reproducible manner.